Drugs Affecting the Respiratory System

1. Drugs Affecting the Respiratory System Bronchodilators and Other Respiratory Drugs

2. Respiratory System DrugsLower Respiratory Tract Diseases • Asthma • Emphysema • Chronic bronchitis

3. Respiratory System DrugsAsthma • Recurrent and reversible shortness of breath • Airways become narrow as a result of: • Bronchospasm • Inflammation & Edema of the bronchial mucosa • Production of viscid mucus • Alveolar ducts/alveoli remain open, but airflow to them is obstructed • Symptoms • Wheezing • Difficulty breathing

4. Respiratory System DrugsAsthma • Status asthmaticus • Prolonged asthma attack that does not respond to typical drug therapy • May last several minutes to hours • Medical emergency

5. Respiratory System DrugsChronic Bronchitis • Continuous inflammation of the bronchi and bronchioles • Often occurs as a result of prolonged exposure to bronchial irritants • Characterized by • Hypoxemia • Chronic productive cough • “Blue Bloater”

6. Respiratory System DrugsEmphysema • Air spaces enlarge as a result of the destruction of alveolar walls • The surface area where gas exchange takes place is reduced • Effective respiration is impaired • Characterized by: • Increased paCO2 - respiratory acidosis • Difficulty exhaling – pursed lip breathing • “Pink Puffer”

7. Respiratory System DrugsCOPD Drugs • Long-term control • Antileukotrienes • cromolyn • Inhaled steroids • Long-acting β2-agonists • Quick relief • Intravenous systemic corticosteroids • Short-acting inhaled β2-agonists

8. Respiratory System Drugs • Bronchodilators • β-adrenergic agonists • Xanthine derivatives • Anticholinergics • Antileukotrienes • Corticosteroids

9. Respiratory System DrugsBronchodilators: β-Agonists Large group, sympathomimetics Used during acute phase of asthmatic attacks Quickly reduce airway constriction Stimulate β2-adrenergic receptors throughout the lungs

10. Respiratory System Drugs Bronchodilators: β-Agonists Three types • Nonselective adrenergics • Stimulate α, β1 (cardiac), and β2 (respiratory) receptors • Example: epinephrine • Nonselective β-adrenergics • Stimulate both β1 and β2 receptors • Example: metaproterenol • Selective β2 drugs • Stimulate only β2 receptors • Example: albuterol (Proventil)

11. Respiratory System DrugsBronchodilators: β-Agonists Mechanism of Action • Begins at the specific receptor stimulated# • Ends with the dilation of the airways • #Activation of β2 receptors activates cAMP,* which relaxes smooth muscles of the airway and results in bronchial dilation and increased airflow *cAMP = cyclic adenosine monophosphate

12. Respiratory System DrugsBronchodilators: β-Agonists Indications Relief of bronchospasm related to asthma, bronchitis, and other pulmonary diseases Useful in treatment of acute attacks as well as prevention Used in hypotension and shock Used to produce uterine relaxation to prevent premature labor Hyperkalemia—stimulates potassium to shift into the cell

13. α-β (epinephrine) Insomnia Restlessness Anorexia Vascular headache Hyperglycemia Tremor Cardiac stimulation Respiratory System Drugsβ-Agonists: Adverse Effects

14. Respiratory System Drugsβ-Agonists: Adverse Effects β1 and β2 (metaproterenol) • Cardiac stimulation • Tremor • Anginal pain • Vascular headache • Hypotension

15. Respiratory System Drugsβ-Agonists: Adverse Effects β2 (albuterol) • Hypotension OR hypertension • Vascular headache • Tremor

16. Respiratory System Drugs β-Agonists Nursing Implications • Thorough assessment before beginning therapy • Skin color • Baseline vital signs • Respirations (should be between 12 and 24 breaths/min) • Respiratory assessment, including PO2 • Sputum production • Allergies • History of respiratory problems • Other medications

17. Respiratory System Drugs β-Agonists - Nursing Implications • Monitor for therapeutic effects • Decreased dyspnea • Decreased wheezing, restlessness, and anxiety • Improved respiratory patterns with return to normal rate and quality • Improved activity tolerance • Patients should know how to use inhalers and MDIs • Have patients demonstrate use of devices • Monitor for adverse effects

18. Respiratory System Drugs β-Agonists - Patient Education • Patients should be encouraged to have a good state of health • Avoid exposure to conditions that precipitate bronchospasms (allergens, smoking, stress, air pollutants) • Adequate fluid intake • Compliance with medical treatment • Avoid excessive fatigue, heat, extremes in temperature, caffeine • Patients to get prompt treatment for flu or other illnesses • Patients to get vaccinated against pneumonia and flu • Check with their physician before taking any medication, including OTCs • Teach patients to take bronchodilators exactly as prescribed

19. Respiratory System Drugsβ-Agonist DerivativesNsg Implications • Albuterol, if used too frequently, loses its β2-specific actions at larger doses • As a result, β1 receptors are stimulated, causing nausea, increased anxiety, palpitations, tremors, and increased heart rate • Take medications exactly as prescribed • No omissions or double doses • Report insomnia, jitteriness, restlessness, palpitations, chest pain, or any change in symptoms

20. Inhalers:Patient Education • For any inhaler prescribed, ensure that the patient is able to self-administer the medication • Provide demonstration and return demonstration • Ensure the patient knows the correct time intervals for inhalers • Provide a spacer if the patient has difficulty coordinating breathing with inhaler activation • Ensure that patient knows how to keep track of the number of doses in the inhaler device

21. Respiratory System DrugsAnticholinergics Mechanism of Action • Acetylcholine (ACh) causes bronchial constriction and narrowing of the airways • Anticholinergics bind to the ACh receptors, preventing ACh from binding • Result: • bronchoconstriction is prevented • airways dilate • ipratropium bromide (Atrovent) and tiotropium (Spiriva) • Slow and prolonged action • Used to prevent bronchoconstriction • NOT used for acute asthma exacerbations!

22. Respiratory System DrugsAnticholinergics Adverse effects Dry mouth or throat Nasal congestion Heart palpitations Gastrointestinal distress Headache Coughing Anxiety No known drug interactions

23. Respiratory System DrugsBronchodilatorsXanthine Derivatives • Plant alkaloids: • caffeine, theobromine, and theophylline • Only theophylline is used as a bronchodilator • Synthetic xanthines: (IV) theophylline (Aminophylline) (oral) theophylline (Elixophyllin, Theo-Dur)

24. Respiratory System Drugs BronchodilatorsXanthine Derivatives • Increase levels of energy-producing cAMP • This is done competitively inhibiting phosphodiesterase (PDE), the enzyme that breaks down cAMP (cAMP = cyclic adenosine monophosphate) • Result: • decreased cAMP levels, smooth muscle relaxation, bronchodilation, and increased airflow • cardiovascular stimulation: increased force of contraction and increased heart rate, resulting in increased cardiac output and increased blood flow to the kidneys (diuretic effect)

25. Respiratory System Drugs BronchodilatorsXanthine Derivatives • Dilate of airways in asthma, chronic bronchitis, and emphysema • Mild to moderate cases of acute asthma • Adjunct drug in the management of COPD • Not used as frequently due to: • potential for drug interactions • variables related to drug levels in the blood

26. Xanthine Derivatives: Adverse Effects Nausea, vomiting, anorexia Gastroesophageal reflux during sleep Sinus tachycardia, extrasystoles, palpitations, ventricular dysrhythmias Transient increased urination

27. Xanthine Derivatives Nursing Implications • Contraindications: history of PUD or GI disorders • Cautious use: cardiac disease • Timed-release preparations should not be crushed or chewed (causes gastric irritation) • Report to physician: • Palpitations Nausea Vomiting • Weakness Dizziness Chest pain • Convulsions • Interactions with cimetidine, oral contraceptives, allopurinol, certain antibiotics elevate serum xanthine blood levels • Nicotine & caffeine potentiate cardiac effects • St. John’s wort increases metabolism = decrease blood levels

28. Respiratory System DrugsAntileukotrienes Also called leukotriene receptor antagonists (LRTAs) Newer class of asthma drugs Currently available drugs montelukast (Singulair) zafirlukast (Accolate) zileuton (Zyflo)

29. Respiratory System Drugs Antileukotrienes • Leukotrienes • substances released when a trigger, such as cat hair or dust, starts a series of chemical reactions in the body • cause inflammation, bronchoconstriction, and mucus production • Result: coughing, wheezing, shortness of breath

30. Respiratory System DrugsMechanism of Action • Antileukotriene drugs • prevent leukotrienes from attaching to receptors on cells in and in circulation • Inflammation in the lungs is blocked • Asthma symptoms are relieved By blocking leukotrienes: • Prevent smooth muscle contraction of the bronchial airways • Decrease mucus secretion • Prevent vascular permeability • Decrease neutrophil and leukocyte infiltration to the lungs, preventing inflammation

31. Respiratory System DrugsAntileukotrienes - Indications • Prophylaxis and chronic treatment of asthma in adults and children older than age 12 • NOT meant for management of acute asthmatic attacks • montelukast (Singulair) • is approved for use in children ages 2 and older, and for treatment of allergic rhinitis

32. Respiratory System DrugsAntileukotrienes: Adverse Effects zileuton (Zyflo) zafirlukast (Accolate) Headache Headache Dyspepsia Nausea Nausea Diarrhea Dizziness Liver dysfunction Insomnia Liver dysfunction Montelukast (Singulair) has fewer adverse effects

33. Respiratory System DrugsNursing Implications – Pt Ed Ensure that the drug is being used for chronic management of asthma, not acute asthma Teach the patient the purpose of the therapy Improvement should be seen in about 1 week Check with physician before taking any OTC or prescribed medications—many drug interactions Assess liver function before beginning therapy Medications should be taken every night on a continuous schedule, even if symptoms improve

34. Respiratory System DrugsCorticosteroids • Anti-inflammatory!!! • Uses - chronic asthma/COPD exacerbations • Do not relieve acute asthmatic attacks S&S • Oral, IV (quick acting), or inhaled forms • Inhaled forms reduce systemic effects • May take several weeks before full effects are seen

35. Respiratory System DrugsCorticosteroids Mechanism of Action • Stabilize membranes of cells that release harmful bronchoconstricting substances • Also increase responsiveness of bronchial smooth muscle to β-adrenergic stimulation

36. Respiratory System DrugsInhaled Corticosteroids beclomethasone dipropionate (Beclovent, Vanceril) triamcinolone acetonide (Azmacort) dexamethasone sodium phosphate (Decadron Phosphate Respihaler) fluticasone (Flovent, Flonase)

37. Respiratory System DrugsCorticosteroids - Indications Treatment of bronchospastic disorders that are not controlled by conventional bronchodilators NOT considered first-line drugs for management of acute asthmatic attacks or status asthmaticus

38. Respiratory System DrugsCorticosteroids - Adverse Effects Pharyngeal irritation Coughing Dry mouth Oral fungal infections Systemic effects are rare because of the low doses used for inhalation therapy

39. Corticosteroids Nursing Implications – Pt Education Contraindicated in patients with psychosis, fungal infections, AIDS, TB Teach patients to gargle and rinse the mouth with lukewarm water afterward to prevent the development of oral fungal infections If a β-agonist bronchodilator and corticosteroid inhaler are both ordered, the bronchodilator should be used several minutes before the corticosteroid to provide bronchodilation before administration of the corticosteroid

40. Corticosteroids Nursing Implications – Pt Education • Teach patients • to monitor disease with a peak flow meter • use of a spacer device to ensure successful inhalations • keep inhalers and nebulizer equipment clean after uses • Tapering doses of oral corticosteroids

41. Review Doses of xanthine derivatives may need to be reduced in older adult patients. True or false? Explain your answer.  2. The therapeutic blood level of theophylline in the adult is _____________ 3. Theophylline is classified as a _____________ _____________, whereas albuterol (Proventil) and epinephrine (Medinhaler-Epi) are _____________________ ______________. 4. β-agonists are contraindicated in patients with _________ or _________ disorders. Antileukotriene drugs reduce _______________ associated with asthma, and are used for chronic/acute asthma. 6. This antileukotriene drug is US Food and Drug Administration (FDA) approved for use in children 2 years of age and older: ___________________.

42. Review Answers Lower doses in the older adult may be necessary initially and during therapy with close monitoring for adverse effects and toxicity (cardiovascular and central nervous system [CNS] stimulation). 2. The therapeutic blood level of theophylline in the adult is 10 to 20 mcg/mL; some practitioners recommend 5 to 15 mcg/mL 3. Theophylline is classified as a xanthine derivative, whereas albuterol and epinephrine are β-agonist bronchodilators. 4. β-agonists are contraindicated in patients with a high risk of stroke or any cardiovascular disorders, particularly tachydysrhythmias. 5. Antileukotriene drugs reduce inflammation associated with asthma, and are used for chronic asthma. 6. This antileukotriene drug is US Food and Drug Administration (FDA) approved for use in children 2 years of age and older: montelukast (Singulair).

43. Review For each drug listed, state whether it is used for: A. Asthma prophylaxis and maintenance treatment B. Treatment of acute bronchospasm C. Both 1. montelukast (Singulair), an antileukotriene 2. theophylline (Theo-Dur) oral tablets, xanthine-derived 3. fluticasone (Flovent), a synthetic glucocorticoid 4. ipratropium (Atrovent), an anticholinergic 5. albuterol Proventil) inhaler, a β1 agonist 6. epinephrine, intravenous dose, an alpha-beta agonist

44. Review Answers A A (not used as much now for relief of acute symptoms, especially the oral form) A C C 6. B (for the IV form)